Among portable mobile terminals, a smart phone is a device to which computer-replacing functions, such as for example Internet communication and information retrieval, are added, in addition to a cellular phone function. The use of the smart phone has rapidly increased and has come to be commonly used in recent years, owing to the functions and convenience thereof.
In addition, the smart phone may be used as a portable computer, in addition to being used as a portable phone, and enables, for example, Internet communication and facsimile transmission while moving.
The most important feature of such a smart phone is to allow a user to install or delete hundreds of various applications as the user wishes, unlike conventional cellular phones, which were released as finished products and perform only given functions.
Meanwhile, a mobile terminal such as a smart phone is equipped with a proximity sensor, which senses the approach of a specific body part such as the user's hand or a specific object. The proximity sensor may include a transmitter that transmits infrared light and a receiver that senses reflected infrared light, thereby sensing the approach of a person, an object or the like.
In addition, a conventional proximity sensor is configured such that a proximity sensor unit and a printed black band layer for preventing infrared light reflection and diffuse reflection are stacked one above another, and a glass cover is stacked thereon. Accordingly, a transparent window, i.e. a sensor window, on which the proximity sensor is mounted, generally appears black.
However, for example, although it does not matter that the sensor window appears black when a smart phone is manufactured in black, in the case of a white smart phone, the sensor window that appears black may mar the aesthetic design of the smart phone due to the difference in color from the rest of the terminal.
Therefore, although a white layer may be directly printed on a film layer disposed under the glass cover, in this case, reflection and diffuse reflection of light may occur, which prevents proper transmission and reception of infrared light, deteriorating the accuracy of sensing by the sensor.
In order to solve the problem described above, Korean Patent Laid-Open Publication No. 10-2014-0080256 discloses a portable terminal, which includes a terminal main body coupled at an upper surface thereof to a glass cover, a sensor unit mounted in the terminal main body to sense the external state of the terminal main body, and a sensor window mounted between the sensor unit and the glass cover, the sensor window appearing the same color as the terminal main body. With the conventional portable terminal described above, the sensor window, which is a transparent window of an infrared proximity sensor, may appear white using the scattering of light thereof. Accordingly, when the portable terminal has a bright color such as white, the aesthetic appearance of the portable terminal may be improved owing to the similarity of the colors of the portable terminal and the sensor window.
However, because a light-emitting unit and a light-receiving unit of the proximity sensor are located close to each other, crosstalk may occur due to internal diffuse reflection.
In addition, the sensor window stacked on the proximity sensor may reduce the amount of light emitted from the light-emitting unit and the amount of light received by the light-receiving unit.